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Summary Of Significant Accounting Policies (Narrative) (Details) | 12 Months Ended
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Dec. 31, 2024 USD ($) portfolio_segment | Dec. 31, 2023 USD ($) | Dec. 31, 2022 USD ($)
Summary Of Significant Accounting Policies [Line Items] |  |  |
Number of Reportable Segments | portfolio_segment | 1 |  |
Monthly fee charged Dealer in Portfolio Program | $ 599 |  |
Employer matching contribution, match percentage | 100.00% |  |
Matching contribution | 4.00% |  |
Employer matching contribution, additional match percentage | 50.00% |  |
Additional matching contribution | 2.00% |  |
Maximum matching contribution | 5.00% |  |
Recognized compensation expense | $ 10,300,000 | $ 9,400,000 | $ 8,500,000
Threshold to determine likelihood of being sustained | 50.00% |  |
Advertising expense | $ 1,400,000 | 500,000 | $ 1,000,000.0
Cash and Cash Equivalents [Member] |  |  |
Summary Of Significant Accounting Policies [Line Items] |  |  |
Uninsured cash and cash equivalents | 342,700,000 | 12,800,000 |
Restricted Cash And Cash Equivalents [Member] |  |  |
Summary Of Significant Accounting Policies [Line Items] |  |  |
Uninsured cash and cash equivalents | $ 497,000,000.0 | $ 453,700,000 |
Building [Member] |  |  |
Summary Of Significant Accounting Policies [Line Items] |  |  |
Estimated useful lives | 40 years |  |
Building Improvements [Member] |  |  |
Summary Of Significant Accounting Policies [Line Items] |  |  |
Estimated useful lives | 10 years |  |
Data Processing Equipment [Member] |  |  |
Summary Of Significant Accounting Policies [Line Items] |  |  |
Estimated useful lives | 3 years |  |
Software [Member] |  |  |
Summary Of Significant Accounting Policies [Line Items] |  |  |
Estimated useful lives | 5 years |  |
Office Furniture And Equipment [Member] |  |  |
Summary Of Significant Accounting Policies [Line Items] |  |  |
Estimated useful lives | 7 years |  |
Software Development [Member] |  |  |
Summary Of Significant Accounting Policies [Line Items] |  |  |
Estimated useful lives | 5 years |  |

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